Organochlorine Pesticide and Total Petroleum Hydrocarbon Pollution of Ilaje Coastal River Sediments, Ondo State, Nigeria

Abstract

We investigated the presence of organochlorine pesticides (OCPs) and total petroleum hydrocarbons (TPHs) on the surface sediments sampled at the Ilaje coastal river in Ondo State, Nigeria. The samples were taken at five locations along the coast to determine their distribution in surface sediments and identify the input of industrial activities. The identified OCPs included G-BHC, d-BHC, chlorothalonil, alachlor, aldrin, dacthal, heptachlor-epoxide, g-chlordane, and trans-nonachlor, accounting for roughly 99% of the total detectable in the samples. The pesticide concentrations (dry weight) were ≤ 326.98 ng/g, with an average value of 15.49 ng/g. The pesticide levels at the various studied locations were in this order: Idiogba Police > Igbokoda > Idiogba Subu > Ayetoro > Eyunona. Furthermore, considerable negative and positive correlations exist between the various components of chlorinated pesticides. Based on the dry weight, TPH values in the samples ranged from 5.42 to 22.53 ng/g, in the order Eyunona > Idiogba Police > Idiogba Subu > Ayetoro > Igbokoda. Our data suggest that the hydrocarbons in the sediment matrices arise from anthropogenic causes other than oil spillage, such as water transportation and residential waste discharge, storm waters, rural runoff, etc. Although pollution levels are generally low, there is a need for regular monitoring and enforcement of stringent implementation of environmental laws and standards designed to curb any potential environmental pollution arising from oil spills and indiscriminate waste disposals in the coastal community.